Manila, on the island of Luzon, and the nearby province of Rizal bore the brunt of the storm. People huddled on rooftops Sunday waiting on army helicopters to pluck them to safety. Others used ropes to wade through waist-deep muddy waters.

Power and water supply failed in some areas. Roads were rendered impassable, making rescue efforts challenging. Rescue crews were handing out food rations. See incredible images of the flooding »

"Right now the challenge is to find out how many people have actually died and how many people we have to take care of in terms of people who've been displaced," said Richard Gordon, the chairman of the Philippines National Red Cross.

"We're really talking about maybe hundreds of thousands of people," with about 280,000 to 300,000 displaced in the island of Luzon alone, he said.

Though the Philippines is no stranger to floods, Saturday's downpours approached a record, with a month's worth of rain falling within six hours.

The average rainfall for the month of September is 391 mm (15.4 inches), said Gilberto Teodoro, chairman of the National Disaster Coordinating Council.